It is already known to provide pile fabrics wherein the free ends of the pile threads form hooks, or are deformed to a club-shaped or mushroom-shaped configuration. These free ends can hook into or otherwise interengage with the boucle-type loops of a second fabric, to form in this manner a releasable closure when the two fabrics are pushed together. A type of closure utilizing two such fabrics is commercially available under the tradename "VELCRO".
The manufacture of pile fabrics for this purpose is quite complicated, because the different operating steps required must be carried out on different machines. One of these machines for example produces the pile fabric itself, a second machine cuts the pile threads, and a third one effects the deformation of the free ends of the pile threads.
The prior art has proposed a simplication wherein a combination of the several steps is to be effected, and these steps are to be carried out in a single machine and doing the manufacture of the fabric itself. According to this prior-art proposal, two warp sheds are to be formed, wefts are to be inserted into the warp sheds and beaten up, thus forming two superimposed pile fabrics which are thereupon heated to a sufficiently high temperature in order to fix the meltable threads which form a part of the fabric, in a vertical orientation relative to the fabrics and to anchor them therein. Thereupon the two fabrics are to be severed by severing the meltable threads connecting them and the free ends of the thus severed threads are to be deformed under the influence of heat. The separate fabrics, each provided with threads having deformed end portions, are then to be separately withdrawn.
It has been found, however, that even this proposal still has certain disadvantages which require to be rectified. In particular, the meltable threads are fixed only after the weaving operation is completed, i.e. after the weft threads are inserted and beaten up. Since the meltable threads of synthetic plastic material are relatively stiff, this caused difficulties in the formation of the fabrics, i.e. in the proper beating-up of the weft threads. Since thereupon the two major surfaces of the juxtaposed fabrics (thus far still connected) had to be heated, and since the penetration of heat was not adequate to the meltable threads, this did not cause proper bonding and fixing of the multiple threads to the other threads of the fabrics and thus assure their orientation and anchoring in the fabrics, a difficulty which could not be overcome.